Dynojet PC-5, with Autotune, and full exh. system Tune...

I do wish that DJ would put the same effort into their BMSK products, as they do for H-D's. Their Power Vision flash tuner is PFM in a Twin Cam Harley...I love the thing! Probably just not enough folks riding BMW's who also want to tinker with the ECM, to make it worth their while.

I do wish that DJ would put the same effort into their BMSK products, as they do for H-D's. Their Power Vision flash tuner is PFM in a Twin Cam Harley...I love the thing! Probably just not enough folks riding BMW's who also want to tinker with the ECM, to make it worth their while.

Jeff

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Funny how things change. I have a copy of a letter from DJ to Harley riders which was intended to explain why they weren't going to add a Wideband O2 option to the Harley PC III USB, as they had for BMW oil heads.

In the letter they explained that BMW was unique and needed closed loop to function properly but that HDs didn't! The Harley riders felt shortchanged.

"Let us start with why the BMW uses a wide band O2 sensor as part of the unit. The bike already has a "closed loop" circuit as part of the OEM injection system. It does not "auto map" the entire rpm/throttle position range of the fuel map. Generally speaking, the closed loop system only adjusts the fuel curve below 40% throttle. Above that the system is "open loop". The new Wide Band BMW unit only controls the stock "closed loop" area. Outside of that the bike is mapped in the normal fashion, on the dyno.

We would actually prefer not to maintain the closed loop section. Due to the design of the [BMW] OEM injection system it is not possible to bypass it as we do with other models. Closed Loop systems are not the "magic" that most people believe they are. There are a number of problems that keep it from being the best choice for high performance applications."

.... DJ at it's industry best, giving people only tidbits, as they deems it necessary. I think too, that the PC-5 would have great potential, if they did not just send it to market with most of it's features inop in the BMW app. Perhaps when something else becomes available for less money working better, they will wake up...... then again.....perhaps not.

Wow, I'm hoping whoever wrote that DJ letter was encouraged by management to find new opportunities, involuntarily if needed.

Anyway, I'm surprised DJ even tries to hit the bike market, much less specific models. It would seem to me that we are a pretty small market share. Thus my expectations of their equipment and support is pretty low.

.... DJ at it's industry best, giving people only tidbits, as they deems it necessary. I think too, that the PC-5 would have great potential, if they did not just send it to market with most of it's features inop in the BMW app. Perhaps when something else becomes available for less money working better, they will wake up...... then again.....perhaps not.

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+1 Erling.

DJ's decision not to focus on BMSK has nothing to do with it being "too sophisticated" etc.. the Harley Delphi ECM isn't exactly stone age technology either. They focus on it, because H-D is where the money is at, at the moment. The Delphi ECM uses closed loop and open loop areas, knock detection, fuel trims, just like the BMSK. If there were a significant enough demand, they would offer it.

As a side note, Jamie Long at Fuel Moto, is an excellent resource for tuning advice, and offers some of the best pricing and post purchase support of DJ products that I've found. www.fuelmoto.com.

DJ's decision not to focus on BMSK has nothing to do with it being "too sophisticated" etc.. the Harley Delphi ECM isn't exactly stone age technology either. They focus on it, because H-D is where the money is at, at the moment. The Delphi ECM uses closed loop and open loop areas, knock detection, fuel trims, just like the BMSK. If there were a significant enough demand, they would offer it.

As a side note, Jamie Long at Fuel Moto, is an excellent resource for tuning advice, and offers some of the best pricing and post purchase support of DJ products that I've found. www.fuelmoto.com.

Jeff

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Thanks Jeff. I fully agree with your assessment.
The next month will be interesting, as in the next week I will dyno the bike, this time here locally at MSD hq, as a baseline. I will then remove the PC-5/AT combo, and try another Application. If the dyno likes the numbers, after break in, then the pc-5/at will end up in the flea market. The interesting part is where to put the eggs...... Right now the bike simply rips. It runs fantastic, awesome power through out the entire range, but at the expense of efficiency. My gut feeling after months of trials, I personally thinks that it is over fueled, to a point that it cannot be corrected in either the base map, or afr table. I think the key lies in the time factor it takes the AT to correct the BMSK, and the BMSK being confused, and alone in a dark place...... ha ha.... could't resist..... and they are chasing each other. With only 3 hp gain after pc-5/AT, that simply is not good enough for me as mileage stabilized 7 mpg lower than the indicated mpg..... simply not acceptable. I realize that for some that is not important, and that is great, but not for me.
That said we shall see how it goes. Look for a new write up, with a different title.

Will look for your results with great interest! I very much would like to put a cat less set of headers on my bike, and dyno tune it, but I'm being a chicken, and will not make any radical changes until my warranty expires. Theoretically, the Magnusson-Moss Act should cover blatant warrantee refusals, should something go wrong, unrelated to my tinkering; but it would suck to have the motor crap the bed, and have BMW say "too bad, your fault". For now, I will monitor via GS911, and possibly a WB AFR gauge, and try to learn a few things.

Good luck on the dyno tune session; hope it works out well for you. Also, a big thanks for sharing the info, I know from experience that it does not come cheaply!

Will look for your results with great interest! I very much would like to put a cat less set of headers on my bike, and dyno tune it, but I'm being a chicken, and will not make any radical changes until my warranty expires. Theoretically, the Magnusson-Moss Act should cover blatant warrantee refusals, should something go wrong, unrelated to my tinkering; but it would suck to have the motor crap the bed, and have BMW say "too bad, your fault". For now, I will monitor via GS911, and possibly a WB AFR gauge, and try to learn a few things.

Good luck on the dyno tune session; hope it works out well for you. Also, a big thanks for sharing the info, I know from experience that it does not come cheaply!

Jeff

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Thanks Jeff.....
I was hesitant first as well, but the poor performance with the motor trailside made me jump. That along with a good tuner/friend. Unfortunately he had little experience with the BMSK, and we were both clueless regarding the DJ 8GS APP shortcomings. During my testing since this was installed, I did learn a lot though.

One..... I would never put headers+ open pipe without some form of enrichment, simply too lean.

Two..... I would not invest in the DJ/AT combo with stock exhaust system. I would be worried with perhaps plugging of the CAT chasing power.

Normally I would think the Magnusson-Moss act would stand, but I think that the DJ install would be an easy way for the manufacture to wash their hands, as you are tinkering with the motor heavily. I think there now are enough evidence, not just in this thread, that there are clear cut benefits to a small enrichment to the 8GS, and safe to do so.

Thanks Jeff.....
I was hesitant first as well, but the poor performance with the motor trailside made me jump. That along with a good tuner/friend. Unfortunately he had little experience with the BMSK, and we were both clueless regarding the DJ 8GS APP shortcomings. During my testing since this was installed, I did learn a lot though.

One..... I would never put headers+ open pipe without some form of enrichment, simply too lean.

Two..... I would not invest in the DJ/AT combo with stock exhaust system. I would be worried with perhaps plugging of the CAT chasing power.

Normally I would think the Magnusson-Moss act would stand, but I think that the DJ install would be an easy way for the manufacture to wash their hands, as you are tinkering with the motor heavily. I think there now are enough evidence, not just in this thread, that there are clear cut benefits to a small enrichment to the 8GS, and safe to do so.

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Couldn't agree more. I'll have to wait and see if the low speed shortcomings make me crack before the warrantee period expires, or theres a way to enrichen discretely. :)

Couldn't agree more. I'll have to wait and see if the low speed shortcomings make me crack before the warrantee period expires, or theres a way to enrichen discretely. :)

Jeff

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Yeppers...... I fully understand. When you stand at the edge looking down the river your about to jump in, one cannot help thinking about the rocks submerged, that you cannot see. In this case, I think the water is deep enough...... On the next unit install...... We shall see.....

Went to trace the local dyno operators down, here locally. I was told that MSD ignition could do it, but they say they cant, and only other guy is a dynojet dealer, and he started to go on about how great their product was.....etc... etc.... So it became obvious that it was not going to work. Maybe time for another trip up north to Denver is in order..... Never got to try the intake side........ Hmmmmmm.

So back on track.... I found that the difference in what the DJ/AT added in many of the boxes was capped on the ceiling of 25%, that meant if AT were to uphold the target AFR, it actually were in the need of more than 25%..... Or was it.....???? That is the question, as I had very clear indication that it was running rich.... perhaps quite a lot richer that the target 13.2-14.0 it was supposed to be, as indicating by the wideband sensor removed.
Reason that I mention this, is the overall fuel consumption increase ( which was not metered on the computer) was calculated at 15-20%. I came to that conclusion by observing a few fill ups, and calculated the mileage.....compared that to what the computer said. And I saw from 7-9 mpg difference, at a mileage per gallon of around the number 50....... so that is about 14-18% overall.

DJ PC-5/AT wide band O2 sensor removed......

Next to the stock narrow band O2 sensor just removed from the stock headers.....

Looks like my fuel eco is getting low and lower. Bike still said im doing around 40 miles/gallon (us) but i am doing 30 miles/gallon (us) over the last 2 tanks, I have actually slowed down my riding too because of the winter weather. Last winter my average was 40 miles/gallon (us).

Looks like my fuel eco is getting low and lower. Bike still said im doing around 40 miles/gallon (us) but i am doing 30 miles/gallon (us) over the last 2 tanks, I have actually slowed down my riding too because of the winter weather. Last winter my average was 40 miles/gallon (us).

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Wow..... you are even lower that I was. never the less, that is what made me look else where. I have no real answers of what is happening, except my guesses that the BMSK and PC-5/AT do not work well with each other. No body really knows. Many have guesses, and rather good ones, but no buddy really knows.

Yea, will might have a go at a reverse install soon aswell, see if i can get some money back on the pc5 sell online!

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I am cautiously optimistic with the other fueler, that I am testing right now, but only time will tell, as this was great in the beginning, until the fuel mileage tanked. With that bad mileage, bike ran awesome, from the beginning, and that did not change as mileage went down the hill, so I knew it was just wasted fuel.

I have a PC5/AT sitting in a box in my shed. I fitted it at the same time as the Arrow full exhaust, took it off after a short while and went back to stock ( not the exhaust, just the PC5) The fuel consumption was crap, and I did have it dyno'd by someone who knew what they where doing. I have no definitive figures but at around 120km/hr I used all 36 litres in the main and TT tank in just about 600km. It also didn't seem to make any difference to the way the bike ran.